1. Field of Invention
The invention relates to an ink cartridge and its loading mechanism. In particular, the invention relates to an ink cartridge loading mechanism that utilizes a gear set to change the torque, thereby changing the force on the ink cartridge.
2. Related Art
The ink cartridge loading mechanisms of the inkjet printers can be roughly divided into two types. One type uses a transmission mechanism, such as a guiding screw rod or a belt, to drive the loading mechanism and the ink cartridge thereon to perform a reciprocal motion along a horizontal axis. The paper to be printed is driven by a paper feeding mechanism to pass under the ink cartridge in the vertical direction. The print head ejects ink inside the ink cartridge onto the surface of the paper. The other type uses a fixed loading mechanism. The nozzle array of a print head whose width is larger than or equal to the width of the paper to be printed is employed to directly print on the paper; therefore, the width of the ink cartridge is almost the same as that of the nozzle array of the print head in this mode. In addition, when it is used in color printing models, the ink cartridge usually contains multiple replaceable ink reservoirs for storing inks of different colors, so the page-width array type of ink cartridge has a larger size and more weight. In the above-mentioned two types of inkjet printing mechanisms, the print heads can be integrated in the ink cartridge. Alternatively, they may be separately installed at the bottom of the loading mechanism and connected to the ink cartridge.
The ink cartridges have to be fixed on the loading mechanism to maintain its stability during the printing process and print at correct places. However, they are regularly replaced for ink replenishment. Therefore, the loading mechanism has to provide a good mounting mechanism for fixing and rapid replacement. U.S. Pat. No. 5,971,534 provides an ink cartridge loading mechanism. It mainly includes a receptacle section and a hood section. The ink cartridge is disposed in the receptacle section. With the combination of the rack and pinion, the receptacle section and the ink cartridge are driven to move. The hood section covers one side of the receptacle section and the ink cartridge, so that the ink cartridge does not depart from the receptacle section. U.S. Pat. No. 6,250,750 disposes the ink cartridge in a receptacle section and covers it with a hood which is disposed on an opening of the receptacle section. The hood also suppresses the top of the ink cartridge, thus fixing the ink cartridge in the receptacle section. The mechanism further includes an arm in connection with the hood. As the hood is opened, the print head is lifted from below by the arm for replacement. However, the above-mentioned techniques utilize a stopping-type fixing structure in which a fixing force is limited. For a movable ink cartridge and its loading mechanism, the width of the ink cartridge is small, so the relative size and weight are small and light in weight; therefore, the fixing force is still satisfactory. However, for a page-width array ink cartridge, the fixing force will be insufficient. Currently, most of the page-width array ink cartridges are fixed by screws. This makes replacement very inconvenient.